Also interestingly, the 7th Division became known as ‘The Immortal Seventh”, partly for its exploits during the autumn fighting of 1914 culminating in the 1st Battle of Ypres, but also because it was made up entirely of serving regulars, the first of 5 divisions to be formed of full-strength serving Regulars recalled from Empire (7th, 8th, 27th, 28th, 29th). Under pre-war organization, all British regular battalions serving overseas were kept at full strength (around 1,050 all ranks) with serving regulars. This was in case of unrest or rebellion requiring British troops’ immediate intervention, where sending to the UK for reinforcements would be impracticable.

Meanwhile, battalions stationed in the UK and Ireland were kept at 2/3 full strength (about 650 all ranks) during peace-time. If mobilized for war, they would be brought up to full war strength by mobilized regular reservists (ex-regular soldiers with a continuing military obligation who were required to train/refresh every year of their obligation). The 6 Regular divisions of the BEF thus comprised 2/3 regulars and 1/3 reservists. The Battle of Mons is all the more amazing when you consider that the BEF at that time only had 4 of its 6 infantry divisions available (2 divisions were being kept in the UK meanwhile in case of German invasion), of whom 1/3 were men who had been working in offices, farms, factories and shops just 2 weeks before.